CANBERRA, Australia -- Australia would not end its biggest single export, coal, as part of the government's strategy to curb greenhouse gas emissions, Prime Minister John Howard said Thursday.

Scientist and author Tim Flannery, who last month was chosen as Australian of the Year for his contribution to public understanding of the environment, said late Wednesday that Australia could no longer justify being the world's largest coal exporter given the dire consequences of global warming.

But Howard ruled out cutting coal exports, arguing that Australia's response to climate change must protect jobs in the coal industry.

"You can't do that," Howard told Sky television of the prospect of ending coal exports.

"That would be devastating to many communities throughout Australia; it would cost thousands of jobs -- we are the largest coal exporter in the world," Howard added.

He said his government was investing in the development of new technology that would make coal-fired power generation cleaner.

"We must respond to the challenge of climate change, but we have got to do it in a measured and practical way that doesn't unfairly disadvantage the economy of this country," he added.

Flannery said exporting coal could no longer be considered to be in Australia's national interest.

"The social license of coal to operate is rapidly being withdrawn globally, and no government can protect an industry from that sort of thing occurring," he told Australian Broadcasting Corp. television.

"We've seen it with asbestos; we'll see it with coal," he added.

The opposition center-left Labor Party this week began Parliament's first session of this election year by targeting the center-right government's refusal to sign on to the Kyoto Protocol for reducing greenhouse gas emissions.

Labor backed its calls for Australia to ratify Kyoto and join a global carbon trading system with a landmark U.N. report last week that found with 90 percent certainty that human activity was to blame for catastrophic climate change.

Global warming is likely to be a major issue at elections due this year with most cities facing drinking water shortages because of the worst drought in a century which is dampening economic growth by slashing farm produce.

The government has proposed introducing nuclear power to reduce Australia's dependence on coal -- an option Labor rejects.